This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The utilization of pluripotent cells to form specific cell types requires an understanding of basic metabolism and the factors that affect differentiation. In this study, stem cells are being grown with 13C[unreadable]isotopically labeled substrates such as glucose, and the products of the metabolism are identified by NMR. Cells at different stages of growth and under different conditions are being examined.